In the field of coil coating, a liquid coating is applied via a roller to a continuous strip of material being moved through the coating system, the process and equipment for which is well established. The strip that forms the substrate for the coating is usually steel or aluminum, but may also be of a fabric, plastic, composite or other material. In each case the performance of the final product is dependent on the coating being of a consistent thickness along both the length and the width of the coated strip. Variations in coating thickness can result in variations in color, gloss and surface finish; reductions in anti-corrosion properties and durability; and can even create difficulties in post-processing operations.
Virtually all coating materials change viscosity as a function of temperature. This relationship is both non-linear and inversely proportional. Furthermore, the specific nature of this relationship is unique to each coating formulation. It has been found that variations in temperature exist along the surface of the roller. This can adversely impact coating application and the quality of the resulting applied material. Thus it would be desirable to provide a method and device that regulates the temperature and/or viscosity of the material across the roller and associated continuous strip.
This is clearly demonstrated in FIG. 1 which shows the Viscosity vs. Temperature for a selection of colors of paint all created from the same resin base by the same manufacturer. The variation in each curve is a function of the changes in pigment, fillers, stabilizers, etc. required to get the desired performance from that coating.
Thus, it would be desirable to provide a method and device which addresses such variations and reduces or eliminates the associated problems.